Solving an Inclined Plane Problem: Help for Neil

AI Thread Summary
Neil, a high school senior in AP Physics C, is struggling with a problem involving the acceleration of a block on an inclined plane with a frictional force of 10 N and a 40-degree incline. He attempted to solve it using the equations of motion but arrived at an acceleration of 12.79 m/s², which he believes is incorrect. Neil suspects that the problem cannot be solved accurately without knowing the coefficient of dynamic friction, which is not provided. He is seeking clarification on his approach and what he might have missed in the problem-solving process. The discussion highlights the importance of having all necessary variables to solve physics problems accurately.
Neilthe4th
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Hello, My name is Neil I'm a high school senior in AP Physics C, I'm still taking Pre-Calculus (I know my counselors aren't the brightest) and I'm having trouble with this problem.


Homework Statement


Find the acceleration of the block down the plane.

I have a picture with a block on an inclined plane with a force vector of frictional force pointing up and parallel to the plane of 10 N

Also, the degree of incline on the plane is 40 degrees from the horizontal

The mass is not provided.

Homework Equations



F=ma
Fy=0
Fgy+Fn=0
Fgy=Fn

Fgx+Ff=ma

Fgx=FgCosθ
Fgy=FgSinθ

µ=Tanθ

The Attempt at a Solution



I have tried setting Ff equal to Fnµ and using it to plug in FgSinθ so that in the equation

(mgSinθTanθ+mgCosθ)/m=a

the m get's crossed out since it is in all of the terms, with this I got

12.79 m/s2

But since I'm never too sure of myself I researched the problem on line and found this
http://www.education.com/study-help/article/inclined-planes1/

which has all of the solutions for what I'm trying to solve. Which let me know that my answer is erroneous. I'd like to know how to solve it, or what did I miss about the problem?
 
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I'll go out on a limb & say it's not solvable unless the coefficient of dynamic friction is given.
 
Nah, it's not given.
 

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